The deleterious effects of the oral habits of thumb sucking and tongue thrusting are well recognized. Such habits develop at birth and are believed to be broadly related to the instinctive sucking reflex associated with breast feeding. Although such habits typically fade after the first year of life, in many cases they do not, and for complex psychological reasons such habits become ingrained as the effected individuals increase in age.
Thumb sucking, or digit sucking, if continued after the first year of life causes a constriction of both the mandibular and maxillary arches, a narrowing of the palate, and a number of other adverse skeletal effects. In severe cases where an adolescent demonstrates the habit, the resulting sequela can involve all of the bony structures below the floor of the cranium. Such results can dramatically affect facial profile with severe skeletal and of course severe orthodontic consequences. This can detract from not only physical appearance but can also cause holistic problems which affect the overall health of an individual. By way of example, such habits can result in or exacerbate airway problems.
As a further example of problems that can result from digit sucking, consider a young toddler with dental arches that have been narrowed due to the habit. The child may then develop a lateral preference to the left or right simply so that he or she can conveniently chew food. This is the classic scenario for the onset of an anterior cross-bite.
As noted, tongue thrusting is another destructive oral habit. It involves an abnormal swallowing sequence. In this regard, it should be appreciated that normal swallowing involves a complex, coordinated cycle of muscle reflexes at the back of the throat, the lower face and the tongue. A person exhibiting a tongue thrusting habit will include a non-necessary additional movement where the tongue is pushed upward toward the front of the palate and forcibly forward against the lingual surface of the anterior teeth. Over time, this destructive habit can cause dramatic flaring of the front teeth accompanied by major diastemas between the teeth. Like thumb sucking, a narrowing of the arch and other abnormal physiology can result. This condition, when combined with a molar Class II retrognathic mandible poses one of the most severe orthodontic conditions encountered by orthodontists.
Two distinct approaches have been proposed for attempting to address the above-noted destructive oral habits. In a first approach, orthodontic appliances are utilized which can be positioned within a mouth to engage the digit or the tongue when the oral habit activity is attempted. Such appliances are of a static nature and may assume a "hay rake" configuration to yield painful feedback upon contact. In the later regard, this kind of negative reinforcement approach has proven to be of questionable efficacy and may result in other problems for a patient.
In a second more recent approach, orthodontic habit retraining devices having a palatally positioned roller have been utilized. The palatally positioned roller provides positive sensory feedback when contacted by the tip of the patient's tongue. One such device known as the "Bluegrass" appliance has been developed by the present inventor to yield positive results. See, Haskell, "An aid to stop thumb sucking: The Bluegrass appliance" Pediatric Dentistry, March/April, 1991 at 83-85. To date, however, devices of this nature have not been widely employed. In this regard, it is noted that the use of such devices has been limited to implementations in which a roller is mounted on a dedicated orthodontic device at the time of fabrication of the device.